From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90C41C433E0 for ; Thu, 9 Jul 2020 15:37:23 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 57BFC2077D for ; Thu, 9 Jul 2020 15:37:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="fruYPevj" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 57BFC2077D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:34342 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jtYby-0000Oe-MF for qemu-devel@archiver.kernel.org; Thu, 09 Jul 2020 11:37:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48764) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jtYZS-0006O7-3X for qemu-devel@nongnu.org; Thu, 09 Jul 2020 11:34:46 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:31750 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jtYZP-0003YJ-I0 for qemu-devel@nongnu.org; Thu, 09 Jul 2020 11:34:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1594308881; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NUUZMKzG3HElZpaU5Bfc1hDOw6I1pjVK5k9m9qb3Gc0=; b=fruYPevjWZXneiDIyU1bSO0f3Kz8HnLNRq4dwz/TYv1FiRvxuPYM5dIhsUgcm8Dcq7O7nu 7V1rBe1Uj3bQnEcGzeqzDTCvRpc72rvphCMU+xjP4EuRJB0qB0tXFcFuCHgMFmbzIclaRk 1WGKSfc9hesq+rfLuomfkmJawDajU3U= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-393-phJc49R_PUiT1PrPoqi9pQ-1; Thu, 09 Jul 2020 11:34:34 -0400 X-MC-Unique: phJc49R_PUiT1PrPoqi9pQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7751219057A2; Thu, 9 Jul 2020 15:34:33 +0000 (UTC) Received: from [10.3.113.207] (ovpn-113-207.phx2.redhat.com [10.3.113.207]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1BEDC5D9C9; Thu, 9 Jul 2020 15:34:29 +0000 (UTC) Subject: Re: [PATCH 0/2] keepalive default To: =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= , Vladimir Sementsov-Ogievskiy References: <20200708191540.28455-1-vsementsov@virtuozzo.com> <20200709083510.GF3753300@redhat.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: Date: Thu, 9 Jul 2020 10:34:29 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <20200709083510.GF3753300@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=207.211.31.120; envelope-from=eblake@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/09 11:02:45 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: den@openvz.org, kraxel@redhat.com, qemu-devel@nongnu.org, armbru@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 7/9/20 3:35 AM, Daniel P. Berrangé wrote: > On Wed, Jul 08, 2020 at 10:15:37PM +0300, Vladimir Sementsov-Ogievskiy wrote: >> Hi all! >> >> We understood, that keepalive is almost superfluous with default 2 hours >> in /proc/tcp_keepalive_time. Forcing user to setup keepalive for the >> whole system doesn't seem right, better setup it per-socket. > > Adding the ability to explicitly configure the keepalive settings makes > sense for QEMU. Completely ignoring system defaults when no explicit > settings are given though is not valid IMHO. We already have the ability to add per-socket keepalive (see commit aec21d3175, in 4.2). I guess what you are trying to further do is determine whether the default value for that field, when not explicitly specified by the user, can have saner semantics (default off for chardev sockets, default on for nbd clients where retry was enabled). But since you already have to explicitly opt-in to nbd retry, what's so hard about opting in to keepalive at the same time, other than more typing? Given that the easiest way to do this is via a machine-coded generation of the command line or QMP command, it doesn't seem that hard to just keep things as they are with explicit opt-in to per-socket keepalive. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org